JPH0195222A - Structure of igniter plug - Google Patents

Abstract

PURPOSE:To make it possible to ignite stably a heating element at a low temperature thereof and to hold the long life of the igniter plug structure by providing a protrusion or a flame holding ring having a flame holding performance at the tip end of the plug. CONSTITUTION:Power is applied to a ceramic heating element 12, and the tip end part of a heating element is red-heated to 900-1,000 deg.C, and thereafter a predetermined quantity of a mixed air 14 is supplied in an ignition torch 9. When a part of the mixed air passes through a flame holding ring 13 of a ceramic igniter plug 11, a vortex flow 15 of a low flow speed most suitable for ignition is formed at the rear stream part of the flame holding ring 11. At the same time, the flame is instantaneously formed by heat energy from the ceramic heating body 12 at the rear stream of the flame holding plate 10. Then, the flame continuously ignites other mixed air supplied in the ignition torch 9, thus completing the ignition of the entire part of the ignition torch. Further, by extending a pretective sleeve 16, it is concurrently used as a protective cover for preventing the breakage of the ceramic heating element as a result.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to an igniter plug for an ignition device, and more particularly to an igniter plug structure that prevents ignition failure and enables reliable ignition.

(2) Prior art Fig. 6 shows an example of the arrangement of the ignition torch and main burner of an industrial oil-fired burner, and Fig. 7 shows an example of the tip of the ignition torch.
In both figures, (a) is a side view, and (b) is a front view. When burning the main burner, first ignite the ignition torch 20 with an ignition source such as the pulse igniter 26, and then ignite the ignition torch 20.
After igniting the main burner with a zero flame, it is combusted.

Conventionally, the above-mentioned pulse igniter 26 is used as the ignition source of the ignition torch 20, but this utilizes the spark discharge generated between the electrodes 36a and 36b as shown in FIG. However, in this pulse igniter, the discharge electrode 36a has a narrow Si ignition area.

If foreign matter adheres between 36b, discharge becomes impossible. Further, there is a problem that the lifespan of the spark plug 3) is very short, about 4000 ignitions, due to the effects of metal deterioration and the like.

In Figures 6 and 7, 19 is an air register, 2
1 is a flame detector for the main burner, 22 is an impeller for the main burner, 23 is a burner throat, 24 is a fuel nozzle for the main burner, 25 is a sleeve for the ignition torch, 27 is an impeller for the ignition torch, and 28 is a fuel injection port for the ignition torch. , 29
30 is a flame detector for the ignition torch, 30 is a fuel pipe for the ignition torch, 32 is a flame holding ring, and 33 is a main burner.

Further, in FIG. 8, 34 is a burner nozzle, 35 is a pulse knife, 37 is fuel in a spray state, and 40 is combustion air.

Recently, a ceramic swing knife 38 as shown in FIG. 9, which uses a ceramic heater, has been developed as an igniter to replace the pulse swing knife. 39 is a ceramic heating element. The ceramic Eve knife 38 has excellent ignition characteristics, as compared to the Pulse Eve knife, the ignition head is about twice as wide and the time required for simultaneous ignition is less than half.

Furthermore, since the tip of the Ceramic Eve Knife 3.8 has excellent heat resistance, the life of the igniter plug is approximately 10 times longer than that of the Pulse Eve Knife, making it an excellent burner ignition source.

However, a common problem with the Pulse Eve knife and Ceramic Swiss knife is that due to the influence of the ignition torch structure, the air flow velocity near the igniter's ignition part becomes high (and the ignitability deteriorates significantly). When igniting fuel under the condition of an air flow velocity of 20 m/s, the minimum required exothermic temperature of the ceramic swirl knife 38 of the conventional shape shown in Fig. 9 is 900 m/s for LPG fuel.
It is ℃. However, as shown in FIG. 5, as the shape of the ignition burner changes, the minimum required heat generation temperature of the ceramic swivel knife 38 increases, causing the empty +; LI at X speed 5Qm,/s
It was found that the temperature was 1050℃ at 'G, which is 150℃ higher than when the air flow rate was 20/3.

The air flow velocity is determined by the sizing of the ignition torch and the amount of air required for combustion of the fuel, and is usually in the range of 10 to 50 m/s depending on the diameter of the ignition torch. .

(3) Problems to be Solved by the Invention The pulse-even knife, which is the ignition hammer of the prior art, has problems in that it has poor ignitability and short life.

Further, even in the case of a ceramic swivel knife that can solve the drawbacks of the pulse swivel knife described above, there is a problem in that the necessary heat generation temperature changes depending on the air flow velocity near the ceramic heating element, leading to a shortened lifespan.

An object of the present invention is to provide a highly reliable igniter plug structure that is capable of stable ignition at a constant exothermic temperature regardless of the air flow velocity.

(4) Means for solving the problem The above purpose is to provide an igniter plug that ignites fuel by making a heating element such as ceramics red-hot, and the projection has a flame-holding function that maintains a stable flame at the tip of the igniter plug. Alternatively, this can be achieved by installing a flame-holding ring.

(5) Effect Generally, when igniting a high-temperature object such as a ceramic heating element, the surface temperature of the object required for ignition increases as the temperature and pressure of the combustion air decrease, and as the flow velocity increases.

In the present invention, by installing a protrusion or a flame-holding ring with a flame-holding function near the ceramic heating element at the tip of the ceramic swivel knife plug, the ceramic Since a low flow rate region with a flow rate of 0 to 5 m/s through which ignition is formed near the heating element, there is no need to raise the temperature of the ceramic heating element even when the combustion air flow rate is high, improving ignition reliability. is significantly improved.

The combustion air temperature and pressure mentioned above have a smaller effect on the object surface temperature required for ignition than the flow velocity, and the initial temperature setting of the ceramic heating element is set at room temperature, atmospheric pressure,
In other words, this is not a problem since it is carried out under the most severe conditions.

(6) Embodiment of the Invention An embodiment of the present invention relating to a ceramic igniter plug structure for a boiler ignition torch is shown in FIG. 1(a).

(b) and Figure 2 (a), (bl, Figure 3 (al,
This will be explained using (b).

The igniter plug of this embodiment has a shape as shown in FIG. It has a structure in which it is fixed with a terminal-side protective tube 4 and a protective sleeve 6 with a flame-holding ring 7 installed thereon is fixed to the terminal-side protective tube 4.

The current flows from the positive side electrode terminal 2 to the socket electric waste 43 of the ceramic heating element 1 shown in FIG.
It has a structure in which the tip of the ceramic heating element 1 is ground to increase its resistance, and when power is applied, only the heating portion 41 at the tip 9
00~1) It is designed to become red hot at 00℃.

In this embodiment, the protective sleeve 6 is attached to the ceramic heating element 1.
The flame-holding ring 7 extends to the tip of the flame-holding ring 7 near the heating part 41.
is installed. Furthermore, fuel and combustion air are supplied to the heat generating section 4.
1; l'1. The middle part of the protective sleeve 6 is formed into a hollow m-shape so that the protective sleeve 6 is hollow.

The flame-holding ring 7 is shown in Fig. 2(a), (b) or Fig. 3(a).

The shape shown in (b) is installed, and the angle (θ) 8 of the flame stabilizing ring edge part is adjusted to form a low velocity vortex flow optimal for ignition on the downstream side of the flame stabilizing ring 7. In the embodiment, it is set to 45@. The more acute the angle of θ, the more likely a vortex is to be formed, and conversely, when θ>90′, almost no vortex is formed.

The flame-holding ring 7 shown in FIG. 2 has protrusions 7a formed on the inner circumference at equal intervals rL1, whereas the J-flame-holding ring 7 shown in FIG.
has a circular inner peripheral surface.

In addition, 42 is an electrode part, 44 is an insulation JJ, and 45 is a filler material.

FIG. 4 shows the state in which the ceramic igniter plug of the present invention is installed in an ignition torch. The ignition torch is fueled with PG, which is mixed with p) J) combustion air and supplied as an air-fuel mixture 14. In addition, the torch diameter is φ40
Because of its small size, the flame holding plate for the ignition torch is usually
The air-fuel mixture is mixed at a high flow rate of Qm/s.

In the ignition sequence ζ, power is applied to the ceramic heating element 12 to make the tip of the heating element red-hot to 900-1000° C., and then a predetermined amount of the air-fuel mixture 14 is supplied into the ignition torch 9. When a part of the air-fuel mixture 14 passes through the flame-holding ring 13 of the ceramic igniter plug 1), the flame-holding ring 1)
At the same time, a vortex flow 15 with a low flow velocity that is optimal for ignition is formed in the downstream part, and at the same time, a ceramic heating element 1 is generated in the downstream part of the flame holding Mi, 10.
Thermal energy from 2 instantly forms a flame.

Next, this continuously ignites other air-fuel mixtures supplied into the ignition torch 9, and ignition of the entire ignition torch is completed. 16 is a protective sleeve.

FIG. 5 shows a comparison result of the required heat generation temperature of the ceramic heating element in the present invention. As a result of comparison under the same ignition conditions, it was found that the ceramic igniter of the present invention can be ignited at 900°C, whereas the conventional ceramic igniter shown in FIG. 9 requires a heat generation temperature of 1050°C. From these results, it was found that by using the ceramic igniter of the present invention, it is possible to always form a stable flame at a low exothermic temperature, regardless of the flow velocity conditions of the air-fuel mixture or air. That is, even if the safety factor is taken into account, the heat generation temperature can be set at 950 to 1000°C, and the problem of shortening the life of the heating element by bringing the set temperature close to the operating limit temperature (1200°C) of the heating element is eliminated.

Furthermore, by extending the protective sleeve of the ceramic igniter plug, it also serves as a protective cover to prevent breakage of the ceramic heating element, significantly improving the operability in handling the ceramic igniter.

(7) Effects of the Invention According to the present invention, by providing the ceramic igniter plug itself with a self-flame stabilizing function, it is not affected by changes in air flow velocity due to the ignition burner structure, etc., so the red-hot temperature of the heating element is low. This allows stable ignition at all times.

Furthermore, since the set temperature of the heating element can be set low, there is an effect that the life of the heating element can be maintained for a long time.

[Brief explanation of the drawing]

FIG. 1 shows the structure of an igniter plug according to an embodiment of the present invention, and FIG. 1(a) is a longitudinal cross-sectional view of the whole, and FIG. 1(b) is a longitudinal cross-sectional view of the main part. Figures 2 and 3 show the specific structure of the flame-holding ring, in which (a) is a front view and (bl is a vertical side view). Figure 4 shows the igniter plug according to the present invention. It is a longitudinal sectional view showing an embodiment incorporated into a torch. Fig. 5 is a diagram for explaining the results of an ignition experiment using the conventional type and the present invention Igna-Ita plug. Fig. 6 ( a) and (b) are a side view and a front view of a commercial oil burner. Fig. 7 (a) and (bl are a side view and a front view of the ignition torch in Fig. 6. Fig. 8 is a conventional Fig. 9 is a conceptual diagram of a conventional ceramic igniter. Fig. 2 (a) (b)
) Figure 3 (a) (b
Novano Figure 5 Figure 6 (a) Figure 7

Claims (4)

[Claims] (1) An igniter plug that ignites fuel by making a heating element made of ceramics or the like red-hot, and an igniter plug structure characterized in that a flame holding part having a flame holding function is provided at the tip of the igniter plug. (2) The igniter plug structure according to claim (1), wherein the flame holding portion is a protrusion. (3) The igniter plug structure according to claim (1), wherein the flame holding portion is a flame holding ring. (4) The edge angle θ of the flame stabilizing ring is 0<θ≦90
The igniter plug structure according to claim (3), characterized in that: .degree.